I think I'm going crazy. I have a simply question that I'm struggling with for some reason.
Why does the below return 'undefined'?
var testvar={};
testvar[1]=2;
testvar[2]=3;
alert(testvar.length);
edit I originally typed testvar[1].length. I knew this to be an error. I meant testvar.length
Because 2 isn't an array, it's a number. Numbers have no length.
Perhaps you meant to write testvar.length; this is also undefined, since objects (created using the { ... } notation) do not have a length.
Only arrays have a length property:
var testvar = [ ];
testvar[1] = 2;
testvar[2] = 3;
alert(testvar.length); // 3
Note that Javascript arrays are indexed starting at 0 and are not necessarily sparse (hence why the result is 3 and not 2 -- see this answer for an explanation of when the array will be sparse and when it won't).
var mode = [];
$("input[name='mode[]']:checked").each(function(i) {
mode.push($(this).val());
})
if(mode.length == 0)
{
alert('Please select mode!')
};
Integer has no method length. Try string
var testvar={};
testvar[1]="2";
alert(testvar[1].length);
If length is undefined you can use:
function count(array){
var c = 0;
for(i in array) // in returns key, not object
if(array[i] != undefined)
c++;
return c;
}
var total = count(array);
testvar[1] is the value of that array index, which is the number 2. Numbers don't have a length property, and you're checking for 2.length which is undefined. If you want the length of the array just check testvar.length
var array=[];
array.push(array); //insert the array value using push methods.
for (var i = 0; i < array.length; i++) {
nameList += "" + array[i] + ""; //display the array value.
}
$("id/class").html(array.length); //find the array length.
obj={};
$.each(obj, function (key, value) {
console.log(key+ ' : ' + value); //push the object value
});
for (var i in obj) {
nameList += "" + obj[i] + "";//display the object value
}
$("id/class").html($(nameList).length);//display the length of object.
Source: Stackoverflow.com